This disclosure relates to a developing device preferably loaded in an image forming apparatus, such as a copier or a printer, and the image forming apparatus provided therewith.
A developing device includes: a developing housing including a developing roller and a spiral screw; and a toner container for toner refilling fitted detachably to the developing housing. Provided at a bottom part of the toner container is an openable and closable toner discharge port, and provided in the developing housing at a position corresponding to the toner discharge port is a toner refill port. When the toner container is fitted to the developing housing and then the toner discharge port and the toner refill port are opened, a toner in the toner container is supplied to a predetermined circulatory conveying path formed in the developing housing.
The circulatory conveying path is composed of an outward conveying path corresponding to the toner refill port; and a returning conveying path corresponding to the developing roller. Each circulatory conveying path is fitted with a stirring screw having a spiral blade disposed around its rotation axis. The toner is cyclically conveyed between the outward conveying path and the returning conveying path by these stirring screws.
In the developing device having such configuration, downstream of the toner refill port of the stirring screw provided in the outward conveying path, a conveyance capability inhibition part is provided which is configured such that a conveyance capability deteriorates locally. By such a conveyance capability inhibition part, near the toner refill port upstream of the conveyance capability inhibition part, a toner accumulation part is formed. If the amount of toner in the accumulation part is large, the toner in this accumulation part closes the toner refill port. If the amount of toner in the accumulation part is small, a gap is formed between the toner refill port and the toner accumulation port, and the toner flows from a toner container side into the developing housing. As described above, in accordance with the amount of toner accumulating in the accumulation part, the amount of toner refilled from the toner container into the developing housing is adjusted.